It is known that tonic labyrinthine reflexes and neck reflexes produce opposite effects on the extensor limb musculature. After the demonstration that both neck input and macular input converge on precerebellar, corticocerebellar and vestibular nuclei neurons, the main aim of our study will be to investigate how the conflict between the neck and the macular input is resolved both at the level of the lateral reticular nucleus, which represents one of the structures transmitting neck and macular inputs to the cerebellar cortex as well as at the level of the lateral vestibular nucleus of Deiters, which receives the inhibitory feed-back from the cerebellar cortex. In particular the responses of individual neurons will be recorded not only during sinusoidal tilt around the longitudinal axis of the whole animal (macular input) or of the body alone while maintaining the head stationary (neck input), but also during rotation of the head while maintaining the body stationary, which leads to costimulation of both neck and macular receptors. The undersigned agrees to accept responsability for the scientific and technical conduct of the project and for provision of required progress reports if a grant is awarded as a result of this application.